Pressure regulating systems



April 5, 1966 Filed Aug. 14, 1962 D. F. THOMAS 3,244,107

PRESSURE REGULAIING SYSTEMS 2 Sheets-Sheet 1 INVENTOR. DAV/0 F THOMAS ATT Y.

April 5, 1966 D. F. THOMAS 3,244,107

PRESSURE REGULATING SYSTEMS Filed Aug. 14, 1962 2 Sheets-sheaf. 2

INVENTOR. DA V/D F 77/0MA8 United States Patent 3,244,107 PRESSURE REGULATING SYSTEMS David F. Thomas, St. Paul, Minn., assignor to Waterous Company, St. Paul, Minn, a corporation of Minnesota Filed Aug. 14, 1962, Ser. No. 216,902 3 Claims. (Cl. 103l7) This invention relates to an improvement in pressure regulating systems for pumps, and pertains more particularly to a system for controlling the discharge pressure of a pump driven by an internal combustion engine.

A feature of the present invention is to maintain the discharge pressure of a pump at a desired value when the pump is being driven by an internal combustion engine. More specifically, the invention has for an aim the adjustment of the engines speed so as to produce the required pump discharge pressure.

A further feature of the invention lies in the ready means for varying the pump pressure to achieve different pressures that might be desired.

Another feature is to provide a pressure regulating system that is adaptable to use in conjunction with existing speed control systems for internal combustion engines that might constitute different constructions.

Another feature of the present system is to cause the engines throttle to close when the pump loses its prime or for any reason experiences a mechanical failure.

Yet another feature resides in the simplicity of the system, the system being of low cost and one which is not apt to get out of order readily.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of the specification;

FIGURE 1 is a somewhat diagrammatic representation of one form the pressure regulating system may constitute, the system being shown in conjunction with a speed sensitive governing valve and carburetor.

FIGURE 2 is another diagrammatic view showing the regulating system in which the regulation is realized through the agency of a vacuum-controlled cylinder that acts directly on the engines throttle without utilizing the particular type of carburetor construction shown in FIG- URE 1.

FIGURE 3 is a sectional view through a portion of the apparatus, the position of the section being indicated by the line 33 in FIGURE 1.

Referring first to FIGURE 1, there will be seen that a pump has been shown and that the pump is driven by an internal combustion engine designated generally by the reference numeral 11.

Associated with the engine 11 is a carburetor indicated in its entirety by the reference numeral 12. Inasmuch as the means for atomizing the fuel in a carburetor is old and well known, this portion of the carburetor has not been illustrated. However, a housing unit 13 that may be considered to be part of the carburetor or installed between the carburetor and the intake manifold of the internal combustion engine has been pictured in order to provide a ready understanding of the manner in which my system functions.

Accordingly, it is to be noted that the duct through which the mixed air and fuel passes has been labeled 14, there actually being two such ducts in the exemplary situation. Within these ducts 14 are throttle plates 15 mounted on a rocker shaft 16. The rocker shaft is actuated through the medium of a governor lever 17 at the lower end of a governor rod 19. Thus, the throttle plates 15 can be pivoted into various angular degrees of closure within the ducts 14.

In the upper portion of the housing unit 13 is a diaphragm 20, the diaphragm 20 being contained Within a chamber 21. Leading to the housing unit 13 is a governor air line 22 that branches into a passage 23 extending upwardly to the upper portion of the chamber 21 above the diaphragm 20 and a passage 24 extending downwardly to a pair of governor by-pass jets 25, 26. The jets 25 and 26 lead into manifold vacuum passages 27 that have communication with the right hand duct 14.

In the embodiment of FIGURE 1, it is planned that a speed sensitive valve 28 be employed for governing purposes. Inasmuch as the function of the speed sensitive valve 28 is merely to slow the speed of the engine 11 when its speed becomes excessive, it is not felt necessary to describe this valve in detail. The valve prevents air from passing through the governor air line to whatever extent is necessary to prevent the excessive over-speed condition from continuing. However, it can be pointed out at this time that there is a fresh-air inlet line 29 that leads to the pres'sure sensitive valve 28. The means for supplying air via th'f'line 29 will be described below.

A pilot valve assembly 30 includes a casing 31 having an upper chamber 32, an intermediate chamber 38, and a lower chamber 33, a divider plate 34 dividing chambers 38 and 33. The plate 34 is formed with a conical seat A 35 with which a valve head 36 cooperates. The valve head 36 is carried on the underside of a diaphragm 37 which separates chamber 38 from chamber 32. The valve head 36 is normally biased upwardly into an open position by a coil spring 39 having a disk 40 at its upper end and an internally threaded sleeve 41 at its lower end. The disk 40 bears against the lower end of the valve head 36 and the sleeve 41 is shiftable in a direction axially of the spring 39 by a threaded adjusting shaft 42 which can be manipulated by a knob 43. Preferably, a notched flange or gear 44 is mounted on the shaft and this flange or gear 44 is normally held from rotation by a ball 45 that is acted against by a coil spring 46. In other words, a spring pressed detent mechanism 44-46 is provided which prevents the shaft 42 from inadvertently turning to upset the adjustment.

To prevent the sleeve 41 from rotation with the shaft 42 and gear 44, the sleeve 41 is provided with a diametrically elongated flange 90 at its lower end against which the spring 39 bears. The ends of the flange 90 are notched or forked as indicated at 91 to accommodate diametrically spaced bolts 92 used to hold the lower portion of the housing assembled. Rotation of the adjusting shaft 42 may then cause axial movement of the sleeve 41, the sleeve being held from rotation by the engagement of the bolts 92 in the notches 91.

The air enters the lower end of the casing 31 through an inlet tube or line 47 having an air filter 49 contained in circuit therewith.

Connected to the discharge or outlet of the pump 10 is a line 50 and leading from the line 50 is a line 51 that enters the chamber 32 above the diaphragm 37 so as to subject the diaphragm 37 to the discharge pressure developed by the pump. Thus, the diaphragm 37 is flexed by'virtue of the particular pressure existing at the discharge end of the pump 10 and the valve head or member 36 will be progressivey closed in relationship to its seat 35 in accordance with its developed pressure.

An additional line 52 is in communication with the line 50 so as to apply the pump discharge to a safety valve 53. The safety valve 53 is relatively simple construction, including a piston or plunger 54 that is biased into a closed position by a coil spring 55. The safety valve 53 when closed blocks the passage of air through a line 56 extending from the chamber 38 below the diaphragm 37 to the fresh-air inlet line 29 through another line 57. However, it is possible to by-pass the valve comprised of the head 36 and the seat 35 plus the safety valve 53 by means of a by-pass line 59 in parallel with these elements. A manually operated two-way valve 69 permits closure of the line 59 when the regulating system is being utilized, yet permits a by-pass action to occur when the pilot valve assembly 30 and the safety valve 53 are not to be used.

Having presented the foregoing description, the operation of the regulating system depicted in FIGURE 1 will readily be appreciated. With the valve head 36 open with respect to its seat 35, it can be seen that air can enter the casing 31 of the pilot valve assembly 30, doing so through the line 47 as indicated by the arrow 61. The flow is upward through the casing 31 from the lower chamber 33, past the valve head 36 and into the lower portion of chamber 32; and as indicated by the arrow 62, the air flow continues on to the safety valve 53. The rate of air flow'is controlled by the degree to which the valve 35, 36 is open. If the pressure developed by the pump 1G is suflicient to open or move downwardly the piston 54, then the flow of air continues to the fresh-air line 29 flowing upwardly as indicated by the arrows 63. Assuming that the speed sensitive valve 28 is open, then air is passed to the governor air line 22 and then divides, some of the air going upwardly through the passage 23 as indicated by the arrow 64 filling the portion of chamber 21 on the upper side of the diaphragm 20. The rest of the air is drawn downwardly as indicated by the arrow 65. Under these conditions, the diaphragm 20 is flexed so as to cause the governor rod 19 to shift the throttle plates into an open position as controlled by the engine throttle. At the same time, any increase in engine speed will cause the pump 10 to operate at a greater speed with the result that an increase in discharge pressure occurs. discharge pressure is reflected into the system by way of the line 50 and the line 51, the direction in which this pressure acts being indicated by the arrow 66. Similarly, the arrow 67 indicates the pressure that is applied to the safety valve 53. As already mentioned, such pressure must be adequate to cause the piston 54 to move downwardly.

When the discharge pressure of the pump increases, the valve head 36 will be urged downwardly due to the increase in pressure to which the diaphragm 37 is subjected with the consequence that the opening between the valve head 3% and its seat 35 will be decreased. The decrease in air flow through the fresh air lines 29, 22 will cause the diaphragm to be flexed accordingly. As the fresh air supply is reduced, air is drawn from the chamber 21, causing the diaphragm 26) to flex upwardly, cutting the engine throttle down and reducing engine speed. Hence the pump discharge pressure will be regulated in a manner corresponding to the particular setting of the pilot valve assembly and the pressure of the pump will be regulated this way.

Should for any reason the pump 10 lose its prime or experience a mechanical failure, then it will be appreciated that the safety valve 53 will automatically close so that the air being supplied via the fresh-air line 29 will be cut off, causing the vacuum to draw air from chamber 21 and raising the diaphragm 20 so that the throttle plates 15 will be rotated toward a closed position.

In summary, then the pilot assembly 30 is responsible for controlling the discharge pressure of the pump it), and the safety valve 53 is responsible for reducing the speed of the engine if there is an inadequate pressure at the discharge end of the pump 10 for any reason, the loss of prime and mechanical failure having been mentioned as two such possible causes.

It is within the scope of the invention to employ throttle control linkage that acts directly on the throttle of the engine 10 where no speed governor is used. Such a system is disclosed in FIGURE 2. A carburetor is generally Shown at 70 and a throttle 71 is employed for controlling The increase in the speed of the internal combustion engine 10. The throttle 71 is equipped with an operating arm 72 and the arm 72 is in turn actuated by a vacuum-controlled operating cylinder denoted generally by the reference numeral 73. This cylinder 73 includes a housing 74 and a single convolution bellows type diaphragm 75. The diaphragm 75 is configured for the reception of a rigid cup 76. A rod 77 is attached to the base of the cup 76. The cup 76 and the diaphragm 75 are urged to the left as shown in FEGURE 2 by means of a coil spring 79. A link 80 is pivotally connected to the projecting end of the rod 77 at one end thereof and is pivotally attached to the previously mentioned carburetor operating arm 72 on the throttle 71 at its other end.

A rod 81 is coupled to a hand control located at a panel (not shown). A flexible line 82 extends into the housing 74 and is connected to a vacuum source 83. The vacuum source could constitute the intake manifold of the engine 10 or possibly a vacuum pump or water ejector.

Inasmuch as the other details of the system are the same and like reference numerals have been applied to these various similar details in FIGURE 2 as was done in FIG- URE 1, it is not necessary to describe these elements again. The operation of the modified system shown in FIGURE 2 is as follows: The rod 77 is moved to the right as viewed in FIGURE 2 to close the throttle 71 when the cylinder 73 is subjected to the vacuum produced by the source 83. This, of course, causes the engine It) of FIGURE 2 to operate at a low speed. At this time, the manually operated valve so and safety valve 54 are closed, and the diaphragm 75 has been moved to the right by vacuum.

It is important that the valve 64) be open at the start of the operation, as otherwise it is impossible to increase the pump speed to build up pump pressure unless this valve 60 is initially open. After the pump has built up sufficiently pressure to keep the safety valve 53 open, then the valve 66 may be turned off to place the regulator into operation.

When the pump it has built up sufficient discharge pressure, the safety valve 53 opens and the pressure within the cylinder '73 is increased so that the rod 77 moves to the left to open the throttle 71 and thus increase the engine speed. A suflicient increase in engine speed will develop a corresponding increase in pump pressure which acts against the diaphragm 37 of the pilot valve assembly to reduce the amount of air flow through the assembly 30. Consequently, the vacuum source draws air from the cylinder to reduce engine speed to reduce the discharge pressure of the pump 10. As with the earlier described embodiment, manual operation is possible by reason of the by-pass valve 60 which only has to be opened in order to switch over to the manual operation when such a type of operation is desired.

From what has been said, it should be evident that in both embodiments the pump pressure is pneumatically regulated by controlling the engine speed within fairly narrow limits so as to always give the required amount of liquid pressure for the service to which the pump 10 is put.

in accordance with the patent statutes, I have described the principles of construction and operation of my improvement in pump regulating systems, and while I have endeavored to set forth the best embodiments thereof, I desire to have it understood that changes may be made. within the scope of the following claims without depart ing from the spirit of my invention.

1 claim:

1. A system for regulating the discharge pressure of a pump driven by an engine having a throttle associated therewith, the system including,

a pneumatically actuated device for moving said throt-- tle into various positions,

a control means including a diaphragm and a normally open valve operated by said diaphragm,

first conduit means for applying said pump pressure to said diaphragm to move said valve toward a closed position,

second conduit means extending between said valve and said device, said valve being in communication with said second conduit means so as to control the amount of air delivered to said device in accordance with the position of said valve,

a normally closed safety valve in said second conduit means between said control means and said device, and

third "conduit means for applying said pump pressure to said safety valve to open said safety valve when said pump pressure has reached a predetermined valve to establish communication between the valve of said control means and said device.

2. The system described in claim 1 including,

fourth conduit means in parallel with the valve of said control means and said safety valve, and

a manually operated valve in said fourth conduit means for by-passing both of said valves when open.

3. A system for regulating the discharge pressure of a pump driven by an engine having a throttle associated therewith, the system including:

a pneumatically actuated device having a diaphragm,

means connecting said diaphragm to said throttle,

means for imposing a vacuum on said diaphragm to close said throttle,

an air conduit for admitting air to said device to reduce said vacuum,

a pilot valve in said air conduit,

said pilot valve including a diaphragm subjected to pump pressure,

a valve member carried by said pilot valve diaphragm to control the flow of air through said conduit,

resilient means normally biasing said pilot valve diaphragm toward open position to admit air to said device,

said pilot valve diaphragm being operable when subjected to sufficient pump pressure to close said valve member to thereby increase said vacuum imposed on said diaphragm in said device, and

a safety valve in said conduit responsive to pump pressure for preventing the flow of air through said conduit until said pump has developed sufficient dis charge pressure to open said safety valve.

References Cited by the Examiner UNITED STATES PATENTS 1,929,887 10/ 1933 Gustafson 230-3 2,200,291 5/ 1940 Caget 2303 2,397,443 3/1946 Statham 10316 2,454,073 11/ 1948 Mallory 230-3 2,609,755 9/1952 Griswold 103-17 3,101,670 8/1963 Olson 10317 LAURENCE V. EFNER, Primary Examiner. 

1. A SYSTEM FOR REGULATING THE DISCHARGE PRESSURE OF A PUMP DRIVEN BY AN ENGINE HAVING A THROTTLE ASSOCIATED THEREWITH, THE SYSTEM INCLUDING, A PNEUMATICALLY ACTUATED DEVICE FOR MOVING SAID THROTTLE INTO VARIOUS POSITIONS, A CONTROL MEANS INCLUDING A DIAPHRAGM AND A NORMALLY OPEN VALVE OPERATED BY SAID DIAPHRAGM, FIRST CONDUIT MEANS FOR APPLYING SAID PUMP PRESSURE TO SAID DIAPHRAGM TO MOVE SAID VALVE TOWARD A CLOSED POSITION, SECOND CONDUIT MEANS EXTENDING BETWEEN SAID VALVE AND SAID DEVICE, SAID VALVE BEING IN COMMUNICATION WITH SAID SECOND CONDUIT MEANS SO AS TO CONTROL THE AMOUNT OF AIR DELIVERED TO SAID DEVICE IN ACCORDANCE WITH THE POSITION OF SAID VALVE, A NORMALLY CLOSED SAFETY VALVE IN SAID SECOND CONDUIT MEANS BETWEEN SAID CONTROL MEANS AND SAID DEVICE, AND THIRD CONDUIT MEANS FOR APPLYING SAID PUMP PRESSURE TO SAID SAFETY VALVE TO OPEN SAID SAFETY VALVE WHEN SAID PUMP PRESSURE HAS REACHED A PREDETERMINED VALVE SAID ESTABLISH COMMUNICATION BETWEEN THE VALVE OF SAID CONTROL MEANS AND SAID DEVICE. 